Plastic prosthetic tendon



April 6, 1965 B. R. BODELL PLASTIC PROSTHETIC TENDON Filed Jan. 7, 1963Inventor BRUCE R. BODELL 35/ MM, 611mm zMflaeaw United States Patent 03,176,316 PLASTIC PROSTEETIC TENDON Bruce R. Bodeil, 808 PM Ava, RiverForest, Ell. Filed Jan. 7, 1963, Ser. No. 249,818 2 Qlaims. (Cl. 3-1)This invention relates to improvements in plastic tendon prostheses andto methods for effecting improved plastic prosthetic tendon grafts. Moreparticularly, the invention is directed to a tendon substitute which byreason of improved structure, especially end structure, and which, byreason of improved suture methods, obviates, in use, many of theundesirable and objectionable features and the shortcomings of prior artdevices and techniques.

, Up to the present there have been no completely satisfactorytechniques and no uniformly successful procedures by which transectedtendons of the fingers could be reapproximated or replaced by autogenoustendon grafts to give normal finger function, particularly when thetransection occurs in the area of the middle and proximal phal-anges ofthe fingers. The principal cause for this I failure has been adherenceof scar tissue (at the site of tendon suture) to the sheath whichsurrounds the tendon. In many instances, the overall result has beenimmobiliza tion of the tendon. Attempts to prevent adhesion have metwith only limited success, and because of these frequent adhesions,neither primary repeir nor delayed autogenous tendon grafting hasyielded consistently good funcare also suitable.

Teflon grafts have been used in the prior art, to replace the extensorcommunis or anterial tibial tendons of dogs. These particular tendonswere selected for research, experimentation, investigative work, andtesting because,

being covered by sheaths where they pass beneath an extensorretinaculum, they present problems which approximate very closelysimilar problems which must be considered in dealing with other fiexortendons, such as tendons of the fingers in the human.

In prior art plastic prosthetic tendon research and investigations,grafts of closely woven or braided Teflon, coated with liquid Teflon toprevent tissue ingrowth, have been used. A bifurcation V was provided ateach end of the prosthetic tendon. The arms of the bifurcation were flatbars of limited flexibility. These Y bars were sutured to the tendonends, either with Teflon or with mattress sutures of 4-0 silk. Whilethese plastic prosthetic tendons and the suturing techniques used haveproduced encouraging results in initial investigations, they have notbeen completely successful in several important applications,particularly when directed to transections in the area of the middle andproximal phalanges of the fingers. Frequently, the failures were due toscar tissue which formed at the site of tenton suture, where the bars ofthe plastic tendons were sutured to the living tendon. This scar tissuesadhered to the sheath which surrounds the tendon and the tendon wasimmobilized.

The principal object of the present invention is to provide an improvedprosthetic tendon which is acceptable to and compatible with humantissues and which will glide freely in the tissues to ensure adequatemotion of the part controlled.

Another important object is to provide an improved 3,l76,3l6 PatentedApr. 6, 1955 end structure for joining prosthetic tendons to naturalliving tendons or other tissues.

Still another object of the invention is to provide a prosthetic tendonin which the junction of the prosthetic with the living tendon is at asite away from the tendon sheath.

Related important objects of the present invention are to provideimproved overall structures for prosthetic tendons; to provide improvedmethods of joining prosthetic tendons to living tendons and to musclesand other tissues; to provide an improved prosthetic tendon which can bejoined with living tendon in a manner to avoid disruption when usual andordinary stresses are imposed after healing has occurred; to provide aprosthetic tendon which can be used to replace a transected tendon or afixed tendon; to provide a prosthetic tendon which may be used toreplace not only transected tendons, but which may also be used as areplacement in the case of destruction of tendons anywhere in the bodywhere destruction of the natural tendon, as for example throughcrushing, burns, or missile injuries, has been so extensive as topreclude reapproximation of the severed ends; and to provide aprosthetic tendon which can be connected to a living tendon in a mannerto minimize the formation of motion-impairing scar tissue.

Through a technique of tendon transfer to a nonparalyzed muscle, theprosthesis may be used to restore the function of a body partimmobilized by muscle paralysis. It may also be used for manipulatingparts of limb prosthesis by connection with body muscles through theartificial tendon.

Other objects, advantages, and utilities of the present invention willbecome apparent as the detailed description continues and uponconsideration of the accompanying drawings forming a part of thisspecification and in which like numerals are employed to designate likeparts throughout the same.

FIGURE 1 is a schematic representation of the prosthetic tendon of theinvention;

FIGURE 2 is an end view of the prosthesis of the invention taken alongthe line 22 of FIGURE 1;

FIGURE 3 is an enlarged view of an end detail of the prosthesis of theinvention; and

FIGURE 4 is a schematic idealized representation of the manner of sutureof the prosthesis to a tendon.

Referring now to FIGURE 1, there is shown, for the purpose ofillustrative disclosure, a preferred embodiment of the tendon prosthesisof the invention. The prosthesis, indicated generally at 11, consists ofa body in the form of a strong solid or semi-solid flexible shaft 12having an outer shell or sheath 13 of finely braided, woven, orintertwined inelastic synthetic plastic material such as Teflon, Kel-F,or Silastic, some of the fibers or threads 14 of which continue to andbeyond the ends of the principal structure forming an expanding,conically shaped loosely woven casing or sleeve 15 near the ends andterminating, finally, in a plurality of well defined individual orcomposite strands, threads, or distinct thread-like fibers 16 extendinglongitudinally beyond the ends of the main portion of the device.Instead of constituting a direct extension of the hollow sleeve orcasing 15, the threads may be anchored at a position within the sleeve15 or even to the shaft portion of the prosthesis. As illustrated inFIG- URE 1, the terminating threads extending outwardly of the ends ofthe body of the prosthesis proper are four in number. While more thanfour end threads may be used, if desired, it has been found that fourthreads are adequate for efiecting a good and a balanced suture bondbetween the prosthesis of the invention and the natural tendon to whichit is connected. Three end threads have provided satisfactory suturebonds, and prosthetic tendons having cial problems in establishing abalanced mechanical stresssupporting bond between the prosthesis and thetendon The flexible shaft portion'12' of the prosthetic tendon maybe ofany desired length, depending .upon the particular use and functionintended. In cross-section, as depictedin thepreferred embodiment ofFIGURE 2, the prosthesis is circular. It may be oval or'elliptical, andin certain cases a shaft having a double-bowed or a fairly flatcross-sectional configuration may be a satisfactory form. In mostinstances, the shape of the original natural tendon itself will beadapted for the prosthesis. The shaft 'l2 of the prosthetic tendon isofa braided or of a finely woven mesh of a synthetic m aterial such. asTeflon, Kel-F, Silastic, etc; This structural form imparts bothflexibility and strength to the tendon. Elasticity is should belongenough to, permit their use as sutures for connecting the prosthetictendon to the natural tendon.

' A thread length of 3" to 4" is preferred for many applications.Shorter lengths may be used and special uses may require longerterminal-threads.

' While preferred embodiments of the invention'have to be avoided. Theshaft maybe essentially solid throughf out the major portion of itslength, :but as described and depicted in the drawings, the shaft isformed to provide a loosely woven hollow cylindrical casing or sleeve ateither end (see FIGURE 3). It is into this hollow po'r tion 17 or opencylindrical sleeve-that the end 18 of the of livingtendon fibers 20 toform an integral firm and v 1 strong union between the-prosthetic'tendonand the living been provided;-it will be apparent-that numerousmodifications and variations thereof maybe without de'parting fromunderlying principles of'the invention. It is therefore desired by thefollowing claims to include within the scope of the inventionall' suchvariations and modifications by which substantially the results ofthisEinvention may be-obtained through the use of substantially, thesame or equivalent means. a Y a What is claimed is: 1 i a l. A tendonprosthesis comprisinga solid central section longitudinally alignedbetween and integrally joined to hollow end sleeve sections, saidcentral section having an elongatedv substantially inelastic, flexibleshaft including a tight mesh .lubric plastic outer sheath portionimpenetrable to livingfibers and scar tissue, each said hollow endsleeve section extending longitudinally from" said cenliving tendon 19is inserted at the time theprosthetic tendon is sutured or otherwisefastened to the natural tral section and having anopen end to'receivetherewithin the end of a living tendon, each said hollow end sleevesection being a loose mesh to facilitate ingrowth of living tissue, andeach said hollow end sleeve section having a plurality of endwiseprojecting connection threads for suture into the corresponding tendonfor fixingsuchtentendon 19. The bond developed through ingrowth of the aliving tendon into the sleeve 15:0f the prosthesis is important insupplementing themechanical bond provided by suturing the plasticend-threads" 16-or fibers of'thei prosthetic tendon to the end 18 of theliving tendon 19.

' WhileQas is apparent from the above discussion, it is, important toencourage ingrowth of natural tendon fibers" atthe ends of theprosthetic tendon,]that is, withinthe sleeve 15, :it is essential thatingrowth of tissues into the shaft portion 12 of the prosthesis beavoided and that the shaft be smooth and fiber-impervious. The outersheath shaft by natural fibers and tissuesh Inorder to provide astill'smoother and more impervious outer surface a coat- 13'is tightlywoven or braided to preclude invasion of, the

don to the prosthesis while living tissue ingrows in the loose mesh toform a secure bond,

. 2.;A-tendon prosthesis comprising a: solid central-sectionlongitudinally aligned between and i'nte grally joined to hollow endsleeve sections, saidcentral section 'provid ing an elongatedsubstantially inelastic,fflexible shaft and 1 comprising "a large numberof interwoven 'lubi'ic plastic threads defining a 't'ight mesh outersheath portion impenetrable to living fibers and scartissue, with onlysome of said threads continuing endwisein each direction from saidcentral section to-constitute each end section as a loose mesh sleevehaving'a main length region to facilitate ingrowth of living tissue andhaving an ,open end to receive therewithin the endof a living tendon,and

Y several of the threads comprising each said hollow end The overalldiameter of the shaft 12 will be dictated by the dimensions of theparticular natural tendoni with which it is to be associated 'or whichit is to replace in whole or in part. Ordinarily. the thickness or thediameter willbe" in the order of to /1 inch; The length ofjithe 7loosely woven sleeve or hollowed end portion 15 of the prosthesisshouldbe sufficient to receive the natural tendon segment 22' which isrto beinserted; Ordinarily, a; length of about A to about of an inch .issufiicient'.

For larger tendons, longer. sleeves are to be preferred.

The terminal threads or strands 16 of the prosthesis sleeve sectioncontinuing therebeyond fonsuture into the,

corresponding tendon for fixingsuch'tendon to the prosform a securebond;

'thesis whileliving tissue ingrows in the loose mesh to References Citedby the Examiner 7 UNITEDSTATES PATENTS V 8/38 1 Bowen 3-1 OTHERREFERENCES Williams: Teflon as a Tendon Substitute, from SurgicalForum,'vol. XI, October 1960, pp...'39-40.

RICHARD A. GAUDET, Primary Examiner,

1. A TENDON PROSTHESIS COMPRISING A SOLID CENTRAL SECTION LONGITUDINALLYALIGNED BETWEEN AND INTEGRALY JOINED TO HOLLOW END SLEEVE SECTIONS, SAIDCENTRAL SECTION HAVING AN ELONGATED SUBSTANTIALLY INELASTIC, FLEXIBLESHAFT INCLUDING A TIGHT MESH LUBRIC PLASTIC OUTER SHEATH PORTIONIMPENETRABEL TO LIVING FIBERS AND SCAR TISSUE, EACH SAID HOLLOW ENDSLEEVE SECTION EXTENDING LONGITUDINALLY FROM SAID CENTRAL SECTION ANDHAVING AN OPEN END TO RECEIVE THEREWITHIN THE END OF A LIVING TENDON,EACH SAID HOLLOW END SLEEVE SECTION BEING A LOOSE MESH TO FACILITATEINGROWTH OF LIVING TISSUE, AND EACH SAID HOLLOW END SLEEVE SECTIONHAVING A PLURALITY OF ENDWISE PROJECTING CONNECTION THREADS FOR SUTUREINTO THE CORRESPONDING TENDON FOR FIXING SUCH TENDON TO THE PROSTHESISWHILE LIVING TISSUE INGROWS IN THE LOOSE MESH TO FORM A SECURE BOND.